Re: [PATCH perf/core] perf intel-pt: Fix clang build failure in intel_pt_synth_pebs_sample

Gustavo A. R. Silva
2020-05-19T19:08:16Z

On Sat, May 16, 2020 at 03:35:48PM +0300, Adrian Hunter wrote:
> On 15/05/20 7:41 pm, Arnaldo Carvalho de Melo wrote:
> > Sorry for the top post: Adrian, can you take a look at this?
> >
> > Adrian Hunter was not CCed, Adrian?
>
> From: Adrian Hunter <adrian.hunter@intel.com>
> Date: Sat, 16 May 2020 15:12:28 +0300
> Subject: [PATCH] perf intel-pt: Use allocated branch stack for PEBS sample
>
> To avoid having struct branch_stack as a non-last structure member,
> use allocated branch stack for PEBS sample.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>

Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>>

Thanks, Adrian.
--
Gustavo

> ---
> tools/perf/util/intel-pt.c | 31 +++++++++++++------------------
> 1 file changed, 13 insertions(+), 18 deletions(-)
>
> diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
> index f17b1e769ae4..e4dd8bf610ce 100644
> --- a/tools/perf/util/intel-pt.c
> +++ b/tools/perf/util/intel-pt.c
> @@ -913,11 +913,11 @@ static void intel_pt_add_callchain(struct intel_pt *pt,
> sample->callchain = pt->chain;
> }
>
> -static struct branch_stack *intel_pt_alloc_br_stack(struct intel_pt *pt)
> +static struct branch_stack *intel_pt_alloc_br_stack(unsigned int entry_cnt)
> {
> size_t sz = sizeof(struct branch_stack);
>
> - sz += pt->br_stack_sz * sizeof(struct branch_entry);
> + sz += entry_cnt * sizeof(struct branch_entry);
> return zalloc(sz);
> }
>
> @@ -930,7 +930,7 @@ static int intel_pt_br_stack_init(struct intel_pt *pt)
> evsel->synth_sample_type |= PERF_SAMPLE_BRANCH_STACK;
> }
>
> - pt->br_stack = intel_pt_alloc_br_stack(pt);
> + pt->br_stack = intel_pt_alloc_br_stack(pt->br_stack_sz);
> if (!pt->br_stack)
> return -ENOMEM;
>
> @@ -951,6 +951,9 @@ static void intel_pt_add_br_stack(struct intel_pt *pt,
> sample->branch_stack = pt->br_stack;
> }
>
> +/* INTEL_PT_LBR_0, INTEL_PT_LBR_1 and INTEL_PT_LBR_2 */
> +#define LBRS_MAX (INTEL_PT_BLK_ITEM_ID_CNT * 3U)
> +
> static struct intel_pt_queue *intel_pt_alloc_queue(struct intel_pt *pt,
> unsigned int queue_nr)
> {
> @@ -968,8 +971,10 @@ static struct intel_pt_queue *intel_pt_alloc_queue(struct intel_pt *pt,
> goto out_free;
> }
>
> - if (pt->synth_opts.last_branch) {
> - ptq->last_branch = intel_pt_alloc_br_stack(pt);
> + if (pt->synth_opts.last_branch || pt->synth_opts.other_events) {
> + unsigned int entry_cnt = max(LBRS_MAX, pt->br_stack_sz);
> +
> + ptq->last_branch = intel_pt_alloc_br_stack(entry_cnt);
> if (!ptq->last_branch)
> goto out_free;
> }
> @@ -1720,9 +1725,6 @@ static void intel_pt_add_lbrs(struct branch_stack *br_stack,
> }
> }
>
> -/* INTEL_PT_LBR_0, INTEL_PT_LBR_1 and INTEL_PT_LBR_2 */
> -#define LBRS_MAX (INTEL_PT_BLK_ITEM_ID_CNT * 3)
> -
> static int intel_pt_synth_pebs_sample(struct intel_pt_queue *ptq)
> {
> const struct intel_pt_blk_items *items = &ptq->state->items;
> @@ -1798,25 +1800,18 @@ static int intel_pt_synth_pebs_sample(struct intel_pt_queue *ptq)
> }
>
> if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
> - struct {
> - struct branch_stack br_stack;
> - struct branch_entry entries[LBRS_MAX];
> - } br;
> -
> if (items->mask[INTEL_PT_LBR_0_POS] ||
> items->mask[INTEL_PT_LBR_1_POS] ||
> items->mask[INTEL_PT_LBR_2_POS]) {
> - intel_pt_add_lbrs(&br.br_stack, items);
> - sample.branch_stack = &br.br_stack;
> + intel_pt_add_lbrs(ptq->last_branch, items);
> } else if (pt->synth_opts.last_branch) {
> thread_stack__br_sample(ptq->thread, ptq->cpu,
> ptq->last_branch,
> pt->br_stack_sz);
> - sample.branch_stack = ptq->last_branch;
> } else {
> - br.br_stack.nr = 0;
> - sample.branch_stack = &br.br_stack;
> + ptq->last_branch->nr = 0;
> }
> + sample.branch_stack = ptq->last_branch;
> }
>
> if (sample_type & PERF_SAMPLE_ADDR && items->has_mem_access_address)
> --
> 2.17.1
>
>
>